不同国家土壤生态筛选值比较与启示

Ecological soil screening values among different countries and implication for China

土壤污染生态风险防控是我国土壤环境保护和管理的重要目标。与国外发达国家相比,我国尚未建立基于生态风险的土壤筛选值(土壤生态筛选值),当前有关土壤生态筛选值的综述相对较少。本文系统梳理了美国环境保护局(EPA)、英国环境署(EA)、荷兰住房、空间规划和环境部(VROM)和加拿大环境部长理事会(CCME)制定的土壤生态筛选值,从标准定位、关键受体、暴露途径、推导方法和生物有效性等方面进行对比分析。结果表明,不同国家土壤生态筛选值均考虑了土壤直接接触毒性和经生物富集和生物放大的二次毒性,推导方法普遍采用生态风险评估方法,并充分考虑污染物的生物有效性。然而,当前我国土壤风险管控标准中仅GB 15618—2018农用地标准的部分考虑了污染物对农作物生长和土壤生态的影响,且试验和推导方法与国外筛选值存在较大差异。因此,“十四五”期间建议初步构建我国土壤生态风险评估框架,明确土壤生态筛选值的定位、作用和使用形式,加强代表性物种和典型土壤的陆生生态毒理学等基础研究,建立科学、规范的土壤生态筛选值制定方法和配套指南,尝试建立适合我国土壤区域特征的土壤污染归一方程和淋洗/老化因子,为我国土壤生态筛选值的制定提供建议和参考。

Ecological risk control of soil contamination is an essential target for soil environment protection and management.However,there is still lack of ecological soil screening values(Eco-SSVs)in China and the foundation of the works concerning soil environmental criteria aimed at protecting the terrestrial ecology is also rather weak.In this paper,we systematically compared and analyzed the difference in Eco-SSVs among US Environmental Protection Agency(EPA),UK Environmental Agency(EA),Ministry of Housing,Spatial Planning and the Environment(VORM)of the Netherlands and Canadian Council of Ministers of the Environment(CCME),in aspect of standard positioning,protection objective,derivation method,protective level as well as bioavailability factors.The result showed that both the toxicity induced by direct exposure to soil and the secondary poisoning via bioaccumulation/biomagnification are taken into account for the derivation of Eco-SSVs with a widely applied method of ecological risk assessment in all the aforementioned countries.Meanwhile,the bioavailability of pollutants was well considered.However,among all the current risk control standard of soil contamination in our country,the consideration of ecological risk on crop growth and soil ecosystem was only observed in GB 15618—2018.On such a basis,constructing the framework of soil ecological risk assessment and specifying the role,function and the application form of Eco-SSVs were highly proposed during the 14th Five-Year Plan of our country.Moreover,we highlight strengthening the research of terrestrial ecotoxicity involved in local species and typical soil types in China,establishing the scientific and standardized derivation method of Eco-SSVs as well as the corresponding guideline,and establishing the normalized model and leaching/aging factor,which could provide scientific and technological base for the formulation of Eco-SSVs in our country.